1. Field of the Invention
The present invention relates to disk drive assemblies and, more particularly, to a high capacity, high performance two and one-half inch diameter, low profile disk drive.
2. Description of the Prior Art
Common form factors for hard disk drives are becoming smaller and smaller. Over the years disk diameters have been incrementally reduced from 24" to 14" to 101/2" to 8" to 51/4" to 31/2" to 21/2", 1.8" and recently a 1.3 inch disk drive was announced. Currently, 31/2 and 21/2 inch drives are in widespread use in low end systems, personal computers and lap top computers. To obtain as much data storage capacity in these small drives as practically possible, it is necessary to maximize the number of disks that can be fitted into a standard form factor. Consequently, the spacing between adjacent disks is becoming smaller also. Narrower disk spacings dictate that actuator arms must become thinner and that head/suspension assemblies (HSA's) take on a lower profile.
FIG. 4 shows a conventional head/suspension assembly with a suspension having a flexure 1 and a load beam 2 carrying reinforcing features 3, or such as a separate folded part welded to the top portion of the load beam for reinforcement and load transmission which are solely on the top or away from a slider 4 positioned by the suspension. The load is transmitted from the load beam 2 through a more or less rigid dimple feature 5 which may be a part of the load beam, flexure, or even the slider. The flexure 1 is a thin metal member used to locate the slider 4 in the plane of the disk surface, while allowing the slider to pitch and roll to follow the contours of the disk surface, as well to compensate for the relative motion of the actuator with respect to the disk surface normal direction. The load beam 2 is another thin metal member which has some type of reinforcement to provide resilient spring action which biases the slider 4 toward the surface of the disk so that the slider will fly stably at the appropriate fly-height. The dimple 5 is used to transmit the relatively large slider load rather than transmitting the slider load through the very thin flexure.
An attachment mechanism, such as an arm or a mounting plate, attaches the suspension to the file actuator. The electrical connection between the transducers and the disk file read/write electronics is made by twisted pair wires which run the length of the suspension and extend over the flexure and slider. The ends of the wires are soldered or ultrasonically bonded to the transducer pads on the slider.
While a single HSA is shown, typically back-to-back HSA's are used for the adjacent disk surfaces. As can be seen from FIG. 4, the conventional design requires a very significant amount of disk-to-disk spacing to accommodate the upright reinforcing features of the prior art HSA design. Some conventional designs waste space by including angles between the load beam and the arm to which the load beam is attached.
Historically in small DASD's 51/4" and smaller, a disk drive enclosure for a head/disk assembly (HDA) is fitted into a metal frame commonly called a user frame. This user frame is typically an aluminum die casting or formed from a sheet metal stamping. Generally, a HDA is attached to the user frame via three or four resilient vibration isolators or shock mounts. For these isolators to be effective, space is required between the HDA and the user frame to allow the HDA to move freely in response to external vibration or shocks. Threaded holes are provided at standard locations in the right and left sides and the bottom of the user frame for attaching the disk drive assembly to the using system box. Therefore, the user frame becomes firmly mounted to the using system box, but the HDA is both electrically and mechanically isolated via the vibration/shock isolators. When magneto-resistive (MR) heads are used within a file, electrical isolation is required between the HDA and the user frame.
Known commercially available two and one-half inch hard disk drives are commonly classified as being low capacity and exhibiting relatively low performance. Typically these drives have one or two 65 mm disks and provided a storage capacity of 40 to 120 megabytes (MB). Latencies are in the range of 30 to 35 ms, average access times are greater than 15 ms, and data rates go from 1.5 to 4 MB/sec to/from the media. In most cases, to conserve space and to reduce costs, user frames and shock isolators are not used. Head/disk assemblies (HDA's) include an enclosure screwed directly to the user's box. HDA enclosures typically are simple die cast flat bases with die cast or stamped screwed on covers. These files are aimed at the low end applications, such as personal computers and lap top computers.
For example, the CONNERS CP20XX small 21/2" disk drive series has dispensed with the use of mechanical isolators and the user frame and provide mounting holes directly into the HDA structure. This mounting scheme appears to be satisfactory for those small drives. Other known disk files use three or more stiff shock mounts between the HDA and using system box. Shock mounts that are very stiff are not generally effective for vibration isolation, but provide shock isolation.
Disk files for high end and mid-range applications require a very high capacity, very high performance file, advantageously packaged in a 1 inch high, 21/2 inch form factor. As many disks and transducer heads as possible are put within the HDA enclosure to get maximum storage capacity. Very high volumetric density packaging is required to provide high capacity in the standard form factor. However, convention construction of current 21/2 inch drives cannot achieve either a very high capacity or a very high performance file. A need exists to accomplish high volumetric density packaging, to provide a very high storage capacity, and a high performance disk file.